High-speed printer having improved ribbon tensioning and reversing drive mechanism

ABSTRACT

A high-speed printer of the type having an inked ribbon traversing across a printing area and which is selectively movable to permit character impression and subsequent visibility of the character formed. A pair of pivoted cantilever arms are provided on each side of the printing area of the high-speed printer with a first ribbon guide being mounted adjacent the end of each pivoted cantilever arm. The inked ribbon is supported under tension between the two guides across the width of the printing area and pivoting means are provided for pivoting the cantilever arms in unison about a common pivot axis whereby the printing ribbon is selectively moved as a relatively rigid beam between the printing and viewing positions by pivotal movement of the cantilever arms. A second ribbon guide is mounted on each side of the high-speed printer for supporting the ribbon at points intermediate ribbon takeup and payout spools and the respective first ribbon guides. Each of the second ribbon guides are mounted with their peripheral surface supporting the ribbon in axial alignment with the pivot axis of the pivoted cantilever arm and the ribbon is twisted through substantially a right angle in the space between each second ribbon guide and its associated first ribbon guide so as to extend along a path that bisects the angular movement of the pivoted cantilever arms. Reversible, tensioning ribbon spool drive mechanisms are supported on opposite sides of the high-speed printer for moving the ribbon in either direction between the pair of takeup and payout spools. The spool drive mechanisms are selectively operable alternately to cause the spools to take up or pay out the ribbon and comprise rotatable supporting plates having driving and neutral freewheeling positions. A movable center gear and ratchet arrangement is supported on each supporting plate and coacts with a fixed center gear when the rotatable supporting plate is in its driving position. A spindle for supporting a ribbon spool is rotated by the fixed center gear and includes an actuable finger which is extended upon exhaustion of a ribbon from a spool under conditions where the spool is operating as a payout spool with the supporting plate in its neutral freewheeling position. An interposer lever is actuated by the extended finger upon exhaustion of the ribbon from the spool which then coacts with the ratchet to rotate the rotatable supporting plate from its neutral freewheeling position into a driving position thereby reversing the operation of the spool. A rotatable shaft interconnects the ribbon spool drive mechanisms on opposite sides of the printer with respective connecting links interconnecting the supporting plate of each spool drive mechanism with the rotatable shaft in a manner such that rotation of one of the supporting plates from the neutral freewheeling position to the driving position results in automatic rotation of the opposite supporting plate from the driving position to the neutral freewheeling position thereby providing jam-proof operation.

United States Patent [72] Inventor Donald G. Hebert Rochester, N.Y. [2]]Appl. No. 734,467 [22] Filed June 4, 1968 [45] Patented Jan. 12, 1971 [73 Assignee General Electric Company a corporation of New York [54]HIGH-SPEED PRINTER HAVING IMPROVED RIBBON TENSIONING AND REVERSING DRIVE'MECHANISM 17 Claims, 3 Drawing Figs.

[52] U.S.Cl 197/154, 101/96, [97/160, 101/336 [51] lnt.Cl ..B4lj33/02,B4lj33/5l [50] FieldofSearch 197/151,

154,155, 157, 160l65; 101/96RC,93RC, 100,

Primary Examiner-William B. Penn Attorneys-Lawrence G. Norris, MichaelMasnik, Stanley C;

Corwin, Frank L. Neuhauser, Oscar B. Waddell and Melvin M. Goldenberg lABSTRACT: A high-speed printer of the type having an inked ribbontraversing across a printing area and which is selectively movable topermit character impression and subsequent visibility of the characterformed. A pair of pivoted cantilever arms are provided on each side ofthe printing areaof the.

high-speed printer with a first ribbon guide being mounted adjacent theend of each pivoted cantilever arm. The inked ribbon is supported undertension between the two guides across the width of the printing area andpivoting means are provided for pivoting the cantilever arms in unisonabout a common pivot axis whereby the printing ribbon is selectivelymoved as a relatively rigid beam between the printing and viewingpositions by pivotal movement of the cantilever arms. A second ribbonguide is mounted on each side of the high-speed printer for supportingthe ribbon at points intermediate ribbon takeup and payout spools andthe respective first ribbon guides. Each of the second ribbon guides aremounted with their peripheral surface supporting the ribbon in axialalignment with the pivot axis of the pivoted cantilever arm and theribbon is twisted through substantially a right angle in the spacebetween each second ribbon guide and its associated first ribbon guideso as to extend along a path that bisects the angular movement of thepivoted cantilever arms. Reversible, tensioning ribbon spool drivemechanisms are supported on opposite sides of the high-speed printer formoving the ribbon in either direction between the pair of takeup andpayout spools. The spool drive mechanisms are selectively operablealternately to cause the spools to take up or pay out the ribbon andcomprise rotatable supporting plates having driving and neutralfreewheeling positions. A movable center gear and ratchet arrangement issupported on each supporting plate and coacts with a fixed center gearwhen the rotatable supporting plate is in its driving position. Aspindle for supporting a ribbon spool is rotated by the fixed centergear and includes an actuable finger which is extended upon exhaustionof a ribbon from a spool under conditions where the spool is operatingas a payout spool with the supporting plate in its neutral freewheelingposition. An interposer lever is actuated by the extended finger uponexhaustion of the ribbon from the spool which then coacts with theratchet to rotate the rotatable supporting plate from its neutralfreewheeling position into a driving position thereby reversing theoperation of the spool. A rotatable shaft interconnects the ribbon spooldrive mechanisms on opposite sides of the printer with respectiveconnecting links interconnecting the supporting plate of each spooldrive mechanism with the rotatable shaft in a manner such that rotationof one of the supporting plates from the neutral freewheeling positionto the driving position results in automatic rotation of the oppositesupporting plate from the driving position to the neutral freewheelingposition thereby providing jam-proof operation.

HIGH-SPEED PRINTER HAVING-IMRROVED RIBBON 'TENSIONING AND REVERSINGDRIVE MECHANISM BACKGROUND OF T'l-lE'lNVENTlON terminal printers forcomputer readout, and the like generally utilize electromechanicallyactuated ribbon positioning mechanisms, similar to those employed in:conventional typewriters, wherein a printing, inked ribbonnorrnally isin ,a lowered position to permit visibility of a line being printed whenno printingsignal is being applied, and is selectively 1 raised to theprinting position when printingaction is required.

In such high-speed printers, particularly the type employing a pluralityof discrete printing hammers, the printingribbon must extend unsupportedacross the length-ofthe writing area,

generally a distance of about 17 to 20 inches, and must alsobe readilyreplaceable by an operator of the equipment. These requirements dictatethat ribbon spools andguides be provided'cat accessible locations on thesides of the high-speed "printer in such a manner that theunsupportedribbon is maintainedwunder tension across the entire extent of thewriting area in order that the-ribbon may beraised-andlowered as arelatively rigid beam. It is alsonece ssary that the ribbon .drivemechanismhave-automatic reversing capability.

The nature of the highspeed printer, due to its high speed of operation,precludes incremental movement of1the ribbon in the manner-employed inconventional :typewriters whereby 'ribbon indexingis accomplished as abyproduct of type-bar motion through mechanical association. Hence, thedrive mechanisms for the ribbon spoolers on which the-printingribbonispaidout and taken up must tensionythe ribbon, 'be

located for ready replaceability by'the operator onthe sides of themachine, be-automaticallyreversing and-mustbe independentlyidrivenatalow speed; Reliabilityin operation,-further requires that the reversingand tensioning spool drive mechanism be-essentially jam-proof to :avoid,or minimize mechanical-breakdown. Further, dueto thefact that the inkedribbon must be raised very 'rapidlyfrom the viewing togthe printing"position and then returned,-it is imperative thatthe tensioning of theribbon be accomplished in such .a- -manner that-the tensioned ribbondoes not contribute or add to the inertial force required of theribbonlifting arms.

5 SUMMARY OF THE INVENTION It is therefore an object of the presentinvention to provide a newand improved high-,speedprinter of the itypehaving an inked, :tensioned ribbonthat is 'reversiblytraversed, across a.printing area and that is:selectively moved ,upand'down to. permitcharacter impression andsubsequentvisibility of the character formed,and wherein thewtensioned ribbon .is

. neutrally related to the ribbon lift arm insuchamannerthat the ribbontension does not'adversely influence the ribbon lift arm torque Anotherobject of the invention is the-provisionofa compact, simplified,preassembled ribbon-tensioning and: reversing spool drive mechanism.which is jam-proof andautomatically reversing, and which. does notcontribute. to the. inertia or torque of the-associated ribbonlift arm.ln practicing the invention, a high-speed-printer is providedwhichutilizes an inked ribbon traversingacross azprinting area with theinked ribbon being-selectively raisedand'loweredto permit characterimpressionand subsequent visibility. of the vided on each side of theprinting area and firstribbon guides are mounted adjacent the end ofeachpivoted cantilever arm. The printing ribbon is supported undertension between the two guides across the width of the printing area,andpivoting means are provided for pivoting the cantilever arms inunison about a common pivot axiswhereby the printing ribbon isselectively moved as a relatively rigid beam between the, printing andviewing positions by pivotal movement of the .cantilever arms. A secondribbon guide is mounted on each side of the high-speed printer forsupporting the ribbon at the points intermediate the ribbon takeup andpayout spools and the respective first ribbon guides. .Each secondribbonguide is mounted with its peripheral surface supporting the .ribbon inaxial alignment with the pivot axis of the pivoted cantilever arm, andthe ribbon is twisted through substantially a right angle in the spacebetweeneach second ribbon guide and its respective first ribbon guide sothat it extends along a path that bisects the angleof movement of thepivoted cantilever arms. I

Nonjamming, reversible, tensioning ribbon spool drive mechanisms aresupported on opposite sides of-the high-speed printer-formovingtheribbon in either directionbetween the pair of ribbon takeup and payoutspools undersubstantially constant tension and at some predetermined.low speed. The

spool drive mechanisms areselectively operable alternately to cause thespools to take up or pay out ribbon. Each of the spool drivemechanismscomprise a rotatable supporting plate having driving andneutral freewheeling positions. Amovable centercluster of gears and aratchet is supported on the .supporting plate and coacts with fixedcenter gears under conditions where therotatable supporting plate isinits drivingposition. A spool supporting spindle meshes withand isrotated by the fixed center geararrangement, and includes an actuatingfinger which is released upon exhaustion of ribbon from the spool. Thisonly occurs when the rotatable supporting plate is inits neutralfreewheeling position and the-spool .is operating ,as a payout spool.lnterposer levermeans are provided which areactuated by the actuatingfinger upon the .ribbonon the spool being exhausted."Theinterposer.levenmeanscoactswith the ratchet torotate the rotatablesupporting .plate from its neutral freewheelingposition into ,itsdriving position and thereby automatically reverses the operation of,thmspool drive mechanism. A rotatable shaft isprovidedwhichjnterconnects the ribbon spool drivemechanism von :bothsidespf the high-speed printenand connecting links interconnect therespective rotatable supporting plate of v each ,spopl. ,d,iji vemechanismwith respective ends of the-rotatable shaft. result, rotationof zone =rof the supporting plates from, neutralfreewheeling .position,to thedriving,positionautomaticallyresults: in rotation of the oppositesupporting; plate t'ro m the driving-position to the neutralfreewheelingposition.

Otherobjects, features and many .of the 'attendant d withthe-accompanying drawings,-wherein likerpar p the several FIGS. areidentified by {the same refe r ce character, and-.wherein:

FIG. 1 is a partiallybroken-away perspective viewpf qrlttghspeed-printerconstructed in accordance withthe invention;

FIG; 2 is a sideview of the high-speed printer shownjn ElG. l, andillustrates certain details of the constructionpf the nonjamming,reversible, tensioning ribbon;spooldrive rnechanism comprising apart ofthe invention; and

FIG. 3 is a partial sectional .view of the, spool ,driye mechanism shownin'FlG. 2 taken throughplane DETAILED DESCRIPTION OF THE PREFERREDEMBODlMENT F l6. 1, is a partially disassembled, aperspectivayiew ;Of, ahigh-speed ,printer constructed in accordance ,with thetinvencharacterformed. A pairof pivoted cantilever arms are protion. The high-speedprinter shown-in FlG. l,-utilizes an inked printing ribbon 11 that istraversed back and forth across a printing area generally defined by acylindrical platen 12. Ribbon 11 is selectively raised and lowered by apair of cantilever arms 13 and 14 to permit character impression andsubsequent visibility of the character formed by a suitable lift armmechanism (not show.) for pivotally moving the cantilever arms 13 and 14up and down to selectively place ribbon 11 in printing position adjacentthe platen 12. The lift arm mechanism does not comprise a part of theinstant invention but is described more fully in my copending US.application Ser. No. 734,469 entitled High-Speed Printer HavingControlled Acceleration Ribbon Positioning Differential Mechanism,"filed concurrently herewith. The ribbon 11 is supported at the end ofthe cantilever arms 13 and 14 by a first pair of vertically disposedguides 15 and 16 between which the ribbon 11 is extended and tensionedso that in effect it can be moved up and down as a relatively rigid beamby the cantilever arms 13 and 14. The arrangement is such that with thecantilever arm and hence ribbon 11 in the lowered position, the printedcharacters formed on a recording medium 1 disposed over platen 12, canbe viewed, and the ribbon 11 must be raised by the cantilever arms 13and 14 to place the ribbon in printing position.

With the ribbon 11 in printing position, a high-speed rotating belt offlexible fingers (not shown) rotates the several printing fingers pastthe printing area formed by the surface of platen 12 along a line spacedoutwardly from ribbon 11 with respect to platen 12. The printing fingerseach have a known character such as one of the letters of the alphabet,punctuation mark, number, etc., formed thereon which are scanned pastthe front of the ribbon 11 at a known rate. At an appropriate pointalong the printing area where it is desired to form one of thecharacters on the recording medium disposed over platen 12, aselectively operated hammer (not shown) is actuated to cause the desiredprinting finger to be pressed against the recording medium by way of theinked ribbon 11. The result is to form an inked impression of thecharacter appearing on the selected printing finger which was hit by thehammer. The details of construction of the rotating belt of printingfingers and the printing hammer together with required synchronizingcircuitry to assure proper operation of the printer, do not comprise apart of the instant invention and are not shown. It might be noted,however, that the invention herein described need not necessarily beemployed in conjunction with a high-speed printing arrangement utilizingseparate printing fingers and printing hammers, but could also beemployed with separately actuated hammers having desired charactersformed on their face similar to the arrangement used in conventionaltypewriters, etc.

It will be appreciated from the foregoing description, that with ahigh-speed printer of the type envisioned in FIG. 1, the printing ribbon11 must extend unsupported across the length of the writing area whichmay be a distance on the order of 17 to inches, and must also be readilyreplaceable by an operator of the equipment. These requirements dictatethat the ribbon 11 be maintained under tension so that it providesrigidity to the unsupported ribbon section extending between the guides15 and 16. It is also essential that the tensioned ribbon not contributeto or add to the initial force or torque required to lift the cantileverarms 13 and 14. To overcome this problem, the ribbon 11 is twistedthrough substantially a right angle as shown at 17 and passed over a setof second ribbon guides, one of which is shown at 18, mounted on eachside of the high-speed printer. The second guides 18 support ribbon 11at points intermediate the ribbon takeup and payout spools one of whichis shown at 19 and the respective first ribbon guide, such as 15. As isbest shown in H6. 2 of the drawings, each of the second ribbon guides 18are mounted in such a manner that their peripheral surface whichsupports ribbon 11 is in axial alignment with the pivot axis of thepivoted cantilever arms 13 and 14. Additionally, ribbon 11 is twistedthrough substantially a right angle in the space between the secondribbon guide 18 and its respective first ribbon guide such as 15, and iscaused to extend along a path that bisects the angular movement of thepivoted cantilever arms 13 and 14 as is best illustrated in FIG. 2. Byreason of this arrangement, the tensioned ribbon will cause little, ifany, additional loading or torque on the cantilever arm raising andlowering mechanism.

In order to provide a proper tension to the ribbon 11 and to cause it tobe reversibly moved across the printing area, nonjamming, reversible,tensioning ribbon spool drive mechanisms, one of which is indicatedgenerally at 21, are provided and are supported on opposite sides of thehighspeed printer for moving the ribbon 11 under tension in eitherdirection between the ribbon takeup and payout spools 19. The spooldrive mechanisms 21 are selectively operable alternately to cause thespools 19 to take up or ay out ribbon, and are shown in greater detailin FIGS. 2 and 3 of the drawings. As is best shown in H6. 2 of thedrawings, each of the spool drive mechanisms 21 comprise a rotatablesupporting plate 22 having driving and neutral freewheeling positionsillustrated by solid and dotted lines, respectively. The rotatablesupporting plate 22 is pivoted at 23 and suppons a movable centerclusterof gears and a ratchet which coact with first pinion gear 24 centered atthe pivot point 23 and rotated by a suitable drive shaft coupling 25(shown in FIG. 3) that in turn is driven by a constant speed jack shaftto which the coupling 25 is secured. The cluster of movable center gearsand ratchet is comprised by a first driven gear 26 that meshes with andis driven by the first pinion gear 24. The first driven gear 26 isclustered with a second pinion gear 27 and a ratchet 28, all of whichare rotated in unison about a common center 29D secured to and movablewith a rotatable plate 22. The arrangement is such that the first drivengear 26 is rotatably movable in an are between a driving position of therotatable plate 22 and a neutral freewheeling position for the rotatableplate 22 (shown in dotted outline form) in a manner which permitscontinuous meshing of the first driven gear 26 with the first piniongear 24.

With the rotatable plate 22 in its driving position shown in solid line,the second pinion gear 27 meshes with and drives an intermediate drivengear 31 that is clustered and rotates in synchronism with a third piniongear 32. The third pinion gear 32 meshes with and either drives or isdriven by an output gear 33 which is clustered and rotates insynchronism with a spindle 34 to which the ribbon spool 19 is secured bymeans of a clip spring 35 as best seen in F10. 03 of the drawings.

in operation, assuming that the rotatable plate 22 is in its drivingposition as shown in solid line in H0. 2, then the spool drive mechanism21 on the left-hand side of the high-speed printer will operate in thefollowing manner. As will be described more fully hereinafter, the spooldrive mechanism 21 on the opposite or right side of the high-speedprinter, will have its rotatable plate 22 in the neutral freewheelingposition, and hence will function as the payout spool. The spool 19shown in FIG. 2 for the purpose of the following description will beassumed to be the takeup spool. The jack shaft to which coupling 25, asshown in FIG. 3, and hence pinion 24 is secured is assumed to beconstantly rotating in a clockwise direction as shown in FIG. 2. Pinion24 is constantly meshing with the first drive gear 26 which rotatesabout the center 29 in synchronism with the second pinion 27 and ratchet28. Since it has been assumed that plate 22 is in the driving position,pinion 27 will mesh with and drive the intermediate driven gear 31. Thisresults in rotating third pinion 32 in synchronism with the rotation ofintermediate driven gear 31 and consequently will result in rotatingoutput gear 33. Rotation of output gear 33 results in rotation of thespool spindle 34 so as a consequence the ribbon spool 19 will functionto take up ribbon 11.

In order to tension the ribbon ll properly while it is traversed acrossthe printing area in the above briefly described fashion, the spoolspindle 34 is designed to be resiliently rotatable relative to theoutput gear 33 by reason of a combined compression and torsion spring41, as shown in g f h HG. 3, supported within the core of spindle 34.The spring 41 is compressed between the hub of spindle 34 and outputgear 33 as best shown in FIG. 3 of the drawings, and serves to pressoutput gear 33 against the supporting plate 42' comprising a part of thechassis ,of the ribbon drive. As a result, tensionirig of theribbon 11is act mplished by the frictional drag of output gear 33 against thesupporting plate 42 by reason of the compressive urging of the spring41. Hence, it will be appreciated that whichever one of the two spools19 is operating as the payout spool, this frictional dr'ag will serve totension the ribbon 11 a predetermined amount in a desired fashion.

In addition to being compressed, the spring 41 also is preloadedtorsionaily between the output gear 33 and the spindle 34. Upon the.ribbon spool 'l9being placed upon spindle in the manner best shown inFIG. 3, it is retained in place by the clip 35. Assuming now that thespool is operating as a payout spool, as the ribbon 11 commences tounwind,the spring 41 is abutment 47 of interposer lever 45 is physicallydisengaged by subjected'to additional torsional deflection due to'thefactthat the spindle'34 is allowed to'r'otate' relative to output gear33 for a predetermined angulandistance, approximately 60", at the end ofwhich the spindle 34 and-output gear 33 commence to rotate as a unitwhen the lugon 34 reaches the end of the slot on 33. This relativerotation is made possible by appropriate design of the torsionalcharacteristics of the spring '41 so that the compression due to thespring causes the frictional torque of gear 33 to exceed the woundtorque of the same spring. The resiliency. of spindle 34 relative tooutput gear 33 thus provides a slack 'takeup characteristic for thepurpose of preventing instantaneous slackening of the ribbon 11(particularly during reversing) while the frictional dragof the outputgear 33 limits the ribbon tension. i

For the purpose of the following description, now it will be assumedthat the spool drive mechanism 21 shown-in FIG. 2 has its rotatableplate 22 rotated to the neutral freewheeling position shown in dottedlines and that the spool 19' is being operatedas a payout spool. Underthese conditions, it will be appreciated therefore "that thesecondpinion gear 27 will be rotated toits dotted'line position, and hence isout of mesh with the intermediate driven gear-31. As a consequence, theribbon spool 19, its, spindle 34; output gear 33,-third pinion 32, andthe intermediate driven. gear 31, are all free to rotate in a directionreverse to that previously assumed so that the tape 11 can be moved in apayout direction. Under these assumed conditions, the ribbon 11 on.spool 19 will eventually be exhausted or completely unwound therefrom.

The spindle 34 is designed so that it includes a ribbonsensor 411s shownin Fl GSQ2'and 3, which'is pivotallyand resiliently. mounted within thespindle 34 by means of a pivot 49 anda spring 4,8..The spool l9 isdesigned to include a slot through which the finger or ribbon sensor 43is free to emerge upon the ribbon 11 being completely unwound from thespool. Upon this occurrence, the finger 43 will move outwardly to theposition shown in FIG. 3.

As'the spool 19 continues to unwind, the sensing finger 43 moves from aposition shown at 43A where it emerged in FIG. 2 to the position shownat 438. At position 438, the sensing finger comes into contact with oneend 44 of an elongated interposer lever 45 pivotally supported on themounting plate 42 v at 46. Upon end 44 of interposer lever 45 beingengaged by the emerged sensing finger 43, interposer lever 45 pivots soas .to place an abutment 47 formed on its opposite end into theperiphery of the rotating ratchet 28. As a result, a tooth of theratchet 28 becomes interposed, causing the rotatable supporting plate22to be pivoted about point 23 through the action of the continuouslyrotating pinion 24 that continues to drive gear 26and hence ratchet 28in a counterclockwise direction as shown in FIG. 2. The result is torotate supporting plate 22 into its driving position so that the secondpinion gear 27 is causedto mesh with. androtate the intermediate drivengear 31.

After the rotatable plate 22 has rotated through approximately twothirds of the distance between its neutral freewheeling position anditsdriving position, the interposed the following edge of the tooth ofthe ratchet wheel 28 acting against the inner portion of the interposerlever arm on which abutment 47 is formed. To assure that the rotatableplate 22 continues its motion into the driving position and is heldthere, an overcenter spring 51 is provided which urges the rotatableplate the remainder of the distance into the driving position andmaintains it there. Upon being subsequently switched to its neutralfreewheeling position, as will be described more fully hereinafter, theovercenter spring 51 will serve to maintain the plate in the neutralfreewheeling position.

In order to reverse the position of the rotatable plate on the oppositespool drive mechanism which previously'had been in the driving position,a connecting link 52 is connected between one end 53 of movable plate 22and a crank arm 54L that is secured to and rotates a rotatable shaft 55.The rotataplate 22 to its neutral freewheeling position. Hence, it willbe appreciated that it is impossible for both plates to besimultaneously in the driving position, and hence nonjamming of theapparatus is guaranteed. Reversal of, the supporting plates in the abovemanner, automatically will bring about a reversal in'the direction oftravel of ribbon ll acrossthe printing area of the high-speed printer.

From the foregoing description, it will be appreciated that the presentinvention makes available a new and improved high-speed printer of thetype having an inked,tensioned ribbon that is reversibly traversedacross a printing area, and that is selectively moved up and down topermit character impression and subsequent visibility of the characterformed, and wherein the tensioned ribbon is neutrally related to theribbon lift arm mechanisms in such a manner that the ribbon tension doesnot adversely influence-the lift arm torque. The invention also makesavailable a compact, simplified,,preassembled ribbon tensioning andreversing spool drive mechanism which is jam-proof and automaticallyreversing, and'which does not contribute to the inertia or torque of theassociated ribbon lift arm mechanism.

Having described a preferred embodiment of a high-speed printer havingan improved ribbon tensioning and reversing drive mechanism, it isbelieved obvious that other modifications and variations of theinvention are possible in the light of the above teachings. It istherefore to be understood that changes may be made in the particularembodiment of the vention described which are within the full intendedscope of the invention as defined by the appended claims.

I claim:

1. A nonjamming, reversible, tensioning ribbon spool drive mechanism formoving a ribbon in either direction en a pair of ribbon spools supportedon opposite s ides ofa ork area under substantially constant tension andat i predetennined speed, said drive mechanism being opera temately tocause its spool to take up or pay out n and comprising first pinion gearmeans secured to and rotatedv by suitable drive shaft means, firstdriven gear mean with and driven by said first pinion gear means,porting plate means having said first driven ns rotatably supportedthereon and rotatably .movahl i an .e between a driving position and aneutral freewheeling n in a manner which permits continuous meshing of.first driven gear means with thefirst pinion gear means, a het wheelmeans and second pinion gear means rotatably sup.- ported on saidrotatable supporting plate and rotated in synchronism with said firstdriven gear means, intermediate driven gear means for meshing with androtation by said second pinion gear means upon Said rotatable supportingplate being rotated to the drivingposition third pinion. gear meansrotated by said intemiediate driven gear means, output gear meansmeshing with and driven by said third pinion gear means, spindle meansfor supporting a ribbon spool rotated by said output gear means, saidspindle means including spring loaded finger means held in a depressedposition by a ribbon spool having ribbon wound thereon, the ribbon spoolhaving a slot therein for emergznce of said finger means upon the ribbonbeing completely unwound therefrom under conditions where the spool isoperated to pay out ribbon and the rotatable supporting plate meansassociated therewith is in the neutral freewheeling position, andpivoted lever means having one end engaged by said finger means in theemerged position, the remaining end of said pivoted lever means engagingsaid ratchet wheel upon the lever means being pivoted by the fingermeans and serving to rotate the rotatable supporting plate means fromthe neutral freewheeling position to the driving position whereby saidsecond pinion gear means, which is maintained out of engagement withsaid intermediate driven gear means with the rotatable supporting platemeans in the neutral freewheeling position, is brought into engagementwith said intermediate driven gear means to thereby reverse the actionof the spool and cause it to take up ribbon.

2. A ribbon spool drive according to claim 1 further includingovercenter spring means connected to each of said rotatable supportingplate means for holding the supporting plate means in either the drivingor neutral freewheeling position.

3. A ribbon spool drive according to claim 2 further including rotatableshaft means interconnecting the ribbon spool drive mechanisms onopposite sides of the work area and respective connecting link meansinterconnecting the respective rotatable supporting plate means of eachspool drive mechanism to respective ends of the rotatable shaft means ina manner such that rotation of one of the supporting plate means fromthe neutral freewheeling position to the driving position results inrotation of the opposite supporting plate means from the drivingposition to the neutral freewheeling position.

4. A ribbon spool drive according to claim 3 further includingcompression spring means for forcing the output gear means intofrictional engagement with a supporting member for creating frictionaldrag that serves to tension the ribbon.

5. A ribbon spool drive according to claim 4 wherein said compressionspring means also comprises a torsion spring and is supported withinsaid spindle means, and said spindle means is coupled to the outputdrive gear means at least in part through the medium of said combinedcompression and torsional spring means, said spindle means beingrelatively rotatable a predetermined amount with respect to the outputgear drive means for torsionally preloading the spring means prior tosaid spindle means and output drive gear means rotating as a unit tothereby provide resiliency to the spindle means relative to the outputdrive gear means and prevent instantaneous slackening of the ribbon.

6. A nonjamming, reversible, tensioning ribbon spool drive mechanism formoving a ribbon under substantially constant tension and at somepredetermined speed, in either direction between a pair of ribbon spoolssupported on opposite sides of an intermediate space, said drivemechanism being selectively operable alternately to cause its spool totake up or pay out ribbon, said spool drive mechanism comprisingrotatable supporting plate means having driving and neutral freewheelingpositions, movable center gear and ratchet means supported on saidsupporting plate means, fixed center gear means coacting with saidmovable center gear means with the rotatable supporting plate in thedriving position, spindle means for supporting the ribbon spool androtatable by said fixed center gear means, said spindle means includingfinger means actuable by the exhaustion of ribbon from a spool supportedthereon where the rotatable supporting plate is in the freewheelingposition and the spool is operating as a payout spool, and interposerlever means actuable by said finger means upon the ribbon on a spoolbeing exhausted, said interposer lever means coacting with the ratchetmeans to rotate the rotatable supporting plate means from its neutralfreewheeling position into its driving position thereby reversing theoperation of the spool.

7. A ribbon spool drive according to claim 6 further includingovercenter spring means connected to each of said rotatable supportingplate means for holding the supporting plate means in either the drivingor neutral freewheeling position.

8. A ribbon spool drive according to claim 7 further including rotatableshaft means interconnecting the ribbon spool drive mechanisms onopposite sides of the work area and respective connecting link meansinterconnecting the respective rotatable supporting plate means of eachspool drive mechanism to respective ends of the rotatable shaft means ina manner such that rotation of one of the supporting plate means for theneutral freewheeling position to the driving position results inrotation of the opposite supporting plate means from the drivingposition to the neutral freewheeling position.

9. A ribbon spool drive according to claim 8 further includingcompression spring means for forcing the output gear means intofrictional engagement with a supporting member for creating frictionaldrag that serves to tension the ribbon.

10. A ribbon spool drive according to claim 9 wherein said compressionspring means also comprises a torsion spring and is supported withinsaid spindle means and said spindle means is coupled to the output drivegear means at least in part through the medium of said combinedcompression and torsional spring means, said spindle means beingrelatively rotatable a predetermined amount with respect to the outputgear drive means for torsionally preloading the spring means prior tosaid spindle means and output drive gear means rotating as a unit tothereby provide resiliency to the spindle means relative to the outputdrive gear means and prevent instantaneous slackening of the ribbon.

11. In a high-speed printer including an inked ribbon traversing acrossa printing area and which is selectively movable to permit characterimpression and subsequent visibility of the character formed, a pair ofpivoted cantilever arms, one mounted on each side of the printing area,a first ribbon guide mounted adjacent the end of each pivoted cantilever arm, the ribbon being supported under tension between the twoguides across the width of the printing area, and pivoting means forpivoting the cantilever arms in unison about a common pivot axis wherebythe printing ribbon is selectively moved as a relatively rigid beambetween the printing and viewing positions by pivotal movement of thecantilever arms, the improvement comprising a second ribbon guidemounted on each side of the high-speed printer for supporting the ribbonat points intermediate ribbon takeup and payout spools and therespective first ribbon guides, each second ribbon guide being mountedwith the peripheral surface thereof supporting the ribbon in axialalignment with the pivot axis of the pivoted cantilever arms, the ribbonbeing twisted through substantially a right angle in the space betweeneach second ribbon guide and its respective first ribbon guide andextending along a path that bisects the angle of movement of the pivotedcantilever arms, said high-speed printer further including nonjamming,reversible, tensioning ribbon spool drive mechanisms supported onopposite sides of the high-speed printer for moving the ribbon in eitherdirection between the pair of ribbon takeup and payout spools undersubstantially constant tension and at some predetermined speed, saidspool drive mechanisms being selectively operable alternately to causethe spools to take up or pay out ribbon, each of said spool drivemechanisms comprising rotatable supporting plate means having drivingand neutral freewheeling positions, movable center gear and ratchetmeans supported on said supporting plate means, fixed center gear meanscoacting with said movable center gear means with the rotatablesupporting plate in the driving position, spindle means for supportingthe ribbon spool and rotatable by said fixed center gear means, saidspindle means including finger means actuable by the exhaustion ofribbon from a spool supported thereon where the rotatable supportingplate is in the freewheeling position and the spool is operating as apayout spool, and interposer lever means actuable by said fingerrneansupon the ribbon on a spool being exhausted, said interposer lever meanscoacting with the ratchet means to rotate the rotatable supportingplatemeans from its neutral freewheeling position into its driving positionthereby reversing the operation of the spool.

12. A high-speed printer according to claim 11 further includingrotatable shaft means interconnecting the ribbon spool drive mechanismson opposite sides of the printer and respective connecting link meansinterconnecting the respective'rotatable supporting plate means of eachspool drive mechanism to respective ends of the rotatable shaft means ina manner such that rotation of one of the supporting plate means fromthe neutral freewheeling position to the driving position results inrotation of the opposite supporting plate means from the drivingposition to the neutral freewheeling position.

13. A high-speed printer according to claim 11 further includingnonjamming, reversible, tensioning ribbon spool drive mechanismssupported on opposite sides of the printer for moving a ribbon in eitherdirection between the pair of ribbon takeup and payout spools undersubstantially constant tension and at some predetermined speed, each ofsaid drive mechanisms being operable alternately to cause the spools totake up or pay out ribbon and comprising first pinion gear means securedto and rotated by suitable drive shaft means, first driven gear meansmeshing with and driven by said first pinion gear means, rotatablesupporting plate means having said first driven gear means rotatablysupported thereon and rotatably movable in an are between a drivingposition and a neutral freewheeling position in a manner which permitscontinuous meshing of said first driven gear means with the first piniongear means, ratchet wheel means and second pinion gear means rotatablysupported on said rotatable supporting plate and rotated in synchronismwith said first driven gear means, intermediate driven gear means formeshing with and rotation by said second pinion gear means with saidrotatable supporting plate rotated to the driving position, third piniongear means rotated by said intermediate driven gear means, output gearmeans meshing with and driven by said third pinion gear means, spindlemeans for supporting a ribbon spool rotated by saidoutput gear means,said spindle means including spring loaded finger means held in adepressed position by a ribbon spool having ribbon wound thereon, theribbon spool having a slot therein for emergence of said finger meansupon the ribbon being completely unwound therefrom under conditionswhere the spool is operated to pay out ribbon and the rotatablesupporting plate means associated therewith is in the neutralfreewheeling position, and pivoted lever means having one end engaged bysaid finger means in the emerged position, the remaining end of saidpivoted lever means engaging said ratchet wheel upon the lever meansbeing pivoted by the finger means and serving to rotate the rotatablesupporting plate means from the neutral freewheeling position tothedriving position whereby said second pinion gear means whichpreviously had been maintained out of engagement with said intermediatedriven gear means while the rotatable supporting plate means was in theneutral freewheeling position is brought into engagement with saidintermediate driven gear means to thereby reverse the action of thespool and cause it to take up ribbon.

14. A high-speed printer according to claim 13 further ineludingovercenter spring means connected to each of said rotatable supportingplate means for holding the supporting plate means in either the drivingor neutral freewheeling posi tion.

15, A high-speed printer according to claim 14 further includingrotatable shaft vmeans interconnecting the ribbon spool drive mechanismson opposite sides of the printer and respective connecting link meansinterconnecting the respective rotatable supporting plate means of eachspool drive mechanism to respective ends of the rotatable shaft means ina manner such that rotation of one of the supporting plate means fromthe neutral freewheeling position to the driving position results inrotation of the opposite supporting plate means from the drivingposition to the neutral freewheeling position.

16. A high-speed printer according to claim 15 further includingcompression spring means for forcing the output gear means intofrictional engagement with asupporting member for creating frictionaldrag tat serves to tension the ribbon.

17. A high-speed print er according to claim 16 wherein said compressionspring means also comprises a torsion spring and is supported withinsaid spindle means, and said spindle means is coupled to the outputdrive gear means at least in part through the medium of said combinedcompression and torsional spring means, said spindle means beingrelatively rotatable a predetermined amount with respect to the outputdrive gear means for torsionally preloading the spring means prior tosaid spindle means and output drive gear means rotating as a unit tothereby provide resiliency to the spindle means relative to the outputdrive gear means and prevent instantaneous slackening of the ribbon.

1. A nonjamming, reversible, tensioning ribbon spool drive mechanism for moving a ribbon in either direction between a pair of ribbon spools supported on opposite sides of a work area under substantially constant tension and at some predetermined speed, said drive mechanism being operable alternately to cause its spool to take up or pay out ribbon and comprising first pinion gear means secured to and rotated by suitable drive shaft means, first driven gear means meshing with and driven by said first pinion gear means, rotatable supporting plate means having said first driven gear means rotatably supported thereon and rotatably movable in an arc between a driving position and a neutral freewheeling position in a manner which permits continuous meshing of said first driven gear means with the first pinion gear means, ratchet wheel means and second pinion gear means rotatably supported on said rotatable supporting plate and rotated in synchronism with said first driven gear means, intermediate driven gear means for meshing with and rotation by said second pinion gear means upon said rotatable supporting plate being rotated to the driving position third pinion gear means rotated by said intermediate driven gear means, output gear means meshing with and driven by said third pinion gear means, spindle means for supporting a ribbon spool rotated by said output gear means, said spindle means including spring loaded finger means held in a depressed position by a ribbon spool having ribbon wound thereon, the ribbon spool having a slot therein for emergence of said finger means upon the ribbon being completely unwound therefrom under conditions where the spool is operated to pay out ribbon and the rotatable supporting plate means associated therewith is in the neutral freewheeling position, and pivoted lever means having one end engaged by said finger means in the emerged position, the remaining end of said pivoted lever means engaging said ratchet wheel upon the lever means being pivoted by the finger means and serving to rotate the rotatable supporting plate means from the neutral freewheeling position to the driving position whereby said second pinion gear means, which is maintained out of engagement with said intermediate driven gear means with the rotatable supporting plate means in the neutral freewheeling position, is brought into engagement with said intermediate driven gear means to thereby reverse the action of the spool and cause it to take up ribbon.
 2. A ribbon spool drive according to claim 1 further including overcenter spring means connected to each of said rotatable supporting plate means for holding the supporting plate means in either the driving or neutral freewheeling position.
 3. A ribbon spool drive according to claim 2 further including rotatable shaft means interconnecting the ribbon spool drive mechanisms on opposite sides of the work area and respective connecting link means interconnecting the respective rotatable supporting plate means of each spool drive mechanism to respective ends of the rotatable shaft means in a manner such that rotation of one of the supporting plate means from the neutral freewheeling position to the driving position results in rotation of the opposite supporting plate means from the driving position to the neutral freewheeling position.
 4. A ribbon spool drive according to claim 3 further including compression spring means for forcing the output gear means into frictional engagement with a supporting member for creating frictional drag that serves to tension the ribbon.
 5. A ribbon spool drive according to claim 4 wherein said compression spring means also comprises a torsion spring and is supported within said spindle means, and said spindle means is coupled to the output drive gear means at least in part through the medium of said combined compression and torsional spring means, Said spindle means being relatively rotatable a predetermined amount with respect to the output gear drive means for torsionally preloading the spring means prior to said spindle means and output drive gear means rotating as a unit to thereby provide resiliency to the spindle means relative to the output drive gear means and prevent instantaneous slackening of the ribbon.
 6. A nonjamming, reversible, tensioning ribbon spool drive mechanism for moving a ribbon under substantially constant tension and at some predetermined speed, in either direction between a pair of ribbon spools supported on opposite sides of an intermediate space, said drive mechanism being selectively operable alternately to cause its spool to take up or pay out ribbon, said spool drive mechanism comprising rotatable supporting plate means having driving and neutral freewheeling positions, movable center gear and ratchet means supported on said supporting plate means, fixed center gear means coacting with said movable center gear means with the rotatable supporting plate in the driving position, spindle means for supporting the ribbon spool and rotatable by said fixed center gear means, said spindle means including finger means actuable by the exhaustion of ribbon from a spool supported thereon where the rotatable supporting plate is in the freewheeling position and the spool is operating as a payout spool, and interposer lever means actuable by said finger means upon the ribbon on a spool being exhausted, said interposer lever means coacting with the ratchet means to rotate the rotatable supporting plate means from its neutral freewheeling position into its driving position thereby reversing the operation of the spool.
 7. A ribbon spool drive according to claim 6 further including overcenter spring means connected to each of said rotatable supporting plate means for holding the supporting plate means in either the driving or neutral freewheeling position.
 8. A ribbon spool drive according to claim 7 further including rotatable shaft means interconnecting the ribbon spool drive mechanisms on opposite sides of the work area and respective connecting link means interconnecting the respective rotatable supporting plate means of each spool drive mechanism to respective ends of the rotatable shaft means in a manner such that rotation of one of the supporting plate means for the neutral freewheeling position to the driving position results in rotation of the opposite supporting plate means from the driving position to the neutral freewheeling position.
 9. A ribbon spool drive according to claim 8 further including compression spring means for forcing the output gear means into frictional engagement with a supporting member for creating frictional drag that serves to tension the ribbon.
 10. A ribbon spool drive according to claim 9 wherein said compression spring means also comprises a torsion spring and is supported within said spindle means and said spindle means is coupled to the output drive gear means at least in part through the medium of said combined compression and torsional spring means, said spindle means being relatively rotatable a predetermined amount with respect to the output gear drive means for torsionally preloading the spring means prior to said spindle means and output drive gear means rotating as a unit to thereby provide resiliency to the spindle means relative to the output drive gear means and prevent instantaneous slackening of the ribbon.
 11. In a high-speed printer including an inked ribbon traversing across a printing area and which is selectively movable to permit character impression and subsequent visibility of the character formed, a pair of pivoted cantilever arms, one mounted on each side of the printing area, a first ribbon guide mounted adjacent the end of each pivoted cantilever arm, the ribbon being supported under tension between the two guides across the width of the printing area, and pivoting means for pivoting the cantilever arms in unison about a commOn pivot axis whereby the printing ribbon is selectively moved as a relatively rigid beam between the printing and viewing positions by pivotal movement of the cantilever arms, the improvement comprising a second ribbon guide mounted on each side of the high-speed printer for supporting the ribbon at points intermediate ribbon takeup and payout spools and the respective first ribbon guides, each second ribbon guide being mounted with the peripheral surface thereof supporting the ribbon in axial alignment with the pivot axis of the pivoted cantilever arms, the ribbon being twisted through substantially a right angle in the space between each second ribbon guide and its respective first ribbon guide and extending along a path that bisects the angle of movement of the pivoted cantilever arms, said high-speed printer further including nonjamming, reversible, tensioning ribbon spool drive mechanisms supported on opposite sides of the high-speed printer for moving the ribbon in either direction between the pair of ribbon takeup and payout spools under substantially constant tension and at some predetermined speed, said spool drive mechanisms being selectively operable alternately to cause the spools to take up or pay out ribbon, each of said spool drive mechanisms comprising rotatable supporting plate means having driving and neutral freewheeling positions, movable center gear and ratchet means supported on said supporting plate means, fixed center gear means coacting with said movable center gear means with the rotatable supporting plate in the driving position, spindle means for supporting the ribbon spool and rotatable by said fixed center gear means, said spindle means including finger means actuable by the exhaustion of ribbon from a spool supported thereon where the rotatable supporting plate is in the freewheeling position and the spool is operating as a payout spool, and interposer lever means actuable by said finger means upon the ribbon on a spool being exhausted, said interposer lever means coacting with the ratchet means to rotate the rotatable supporting plate means from its neutral freewheeling position into its driving position thereby reversing the operation of the spool.
 12. A high-speed printer according to claim 11 further including rotatable shaft means interconnecting the ribbon spool drive mechanisms on opposite sides of the printer and respective connecting link means interconnecting the respective rotatable supporting plate means of each spool drive mechanism to respective ends of the rotatable shaft means in a manner such that rotation of one of the supporting plate means from the neutral freewheeling position to the driving position results in rotation of the opposite supporting plate means from the driving position to the neutral freewheeling position.
 13. A high-speed printer according to claim 11 further including nonjamming, reversible, tensioning ribbon spool drive mechanisms supported on opposite sides of the printer for moving a ribbon in either direction between the pair of ribbon takeup and payout spools under substantially constant tension and at some predetermined speed, each of said drive mechanisms being operable alternately to cause the spools to take up or pay out ribbon and comprising first pinion gear means secured to and rotated by suitable drive shaft means, first driven gear means meshing with and driven by said first pinion gear means, rotatable supporting plate means having said first driven gear means rotatably supported thereon and rotatably movable in an arc between a driving position and a neutral freewheeling position in a manner which permits continuous meshing of said first driven gear means with the first pinion gear means, ratchet wheel means and second pinion gear means rotatably supported on said rotatable supporting plate and rotated in synchronism with said first driven gear means, intermediate driven gear means for meshing with and rotation by said second pinion gear means with said rotatable supporting plate rotaTed to the driving position, third pinion gear means rotated by said intermediate driven gear means, output gear means meshing with and driven by said third pinion gear means, spindle means for supporting a ribbon spool rotated by said output gear means, said spindle means including spring loaded finger means held in a depressed position by a ribbon spool having ribbon wound thereon, the ribbon spool having a slot therein for emergence of said finger means upon the ribbon being completely unwound therefrom under conditions where the spool is operated to pay out ribbon and the rotatable supporting plate means associated therewith is in the neutral freewheeling position, and pivoted lever means having one end engaged by said finger means in the emerged position, the remaining end of said pivoted lever means engaging said ratchet wheel upon the lever means being pivoted by the finger means and serving to rotate the rotatable supporting plate means from the neutral freewheeling position to the driving position whereby said second pinion gear means which previously had been maintained out of engagement with said intermediate driven gear means while the rotatable supporting plate means was in the neutral freewheeling position is brought into engagement with said intermediate driven gear means to thereby reverse the action of the spool and cause it to take up ribbon.
 14. A high-speed printer according to claim 13 further including overcenter spring means connected to each of said rotatable supporting plate means for holding the supporting plate means in either the driving or neutral freewheeling position.
 15. A high-speed printer according to claim 14 further including rotatable shaft means interconnecting the ribbon spool drive mechanisms on opposite sides of the printer and respective connecting link means interconnecting the respective rotatable supporting plate means of each spool drive mechanism to respective ends of the rotatable shaft means in a manner such that rotation of one of the supporting plate means from the neutral freewheeling position to the driving position results in rotation of the opposite supporting plate means from the driving position to the neutral freewheeling position.
 16. A high-speed printer according to claim 15 further including compression spring means for forcing the output gear means into frictional engagement with a supporting member for creating frictional drag tat serves to tension the ribbon.
 17. A high-speed printer according to claim 16 wherein said compression spring means also comprises a torsion spring and is supported within said spindle means, and said spindle means is coupled to the output drive gear means at least in part through the medium of said combined compression and torsional spring means, said spindle means being relatively rotatable a predetermined amount with respect to the output drive gear means for torsionally preloading the spring means prior to said spindle means and output drive gear means rotating as a unit to thereby provide resiliency to the spindle means relative to the output drive gear means and prevent instantaneous slackening of the ribbon. 